<link href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/base/jquery-ui.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript">
    $(document).ready(function() {
        $("#[php_property:id]").datepicker({dateFormat: 'yy-mm-dd'});
        $("#[php_property:id]").datepicker($.datepicker.regional['de-CH']);
    });
</script>